Treated alumina hydrate material and uses thereof

ABSTRACT

In a particular embodiment, a particulate material includes alumina hydrate. The particulate material has a 500 psi Compaction Volume Ratio of at least about 4.0 cc/cc.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority from U.S. Provisional PatentApplication No. 60/868,860, filed Dec. 6, 2006, entitled “TREATEDALUMINA HYDRATE MATERIAL AND USES THEREOF”, naming inventors OlivierGuiselin, Nathalie Pluta, Yves Boussant-Roux, and Doruk O. Yener, whichapplication is incorporated by reference herein in its entirety.

FIELD OF THE DISCLOSURE

The present application is related generally to treated alumina hydrateparticulate materials and uses of such particulate materials.

BACKGROUND

Inorganic particulate materials are commonly blended with polymericmaterials to form composite materials. For example, such inorganicparticulate materials may be blended with thermoset polymers to formthermally-stable high-strength polymer composites. In another example,such inorganic particulate materials may be blended with curableelastomeric resins to form reinforced elastomeric composites.

As such, inorganic particulate materials may be used as filler and mayfunction as reinforcements, colorants, or radiation absorbers. Forexample, zirconia and titania are commonly used as whitening agents andultraviolet radiation absorbers. In another example, carbon black istypically used to form dark composites that withstand ultravioletradiation. In a particular example, inorganic particulate materials areused in elastomeric composites for manufacturing tires. In addition tocarbon black, precipitated silica is often used to provide low rollingresistance, for example, to reduce gas consumption, and wet surfacetraction.

In order to reduce fuel consumption, attempts have been made by tiresproducers to obtain tires with low rolling resistance. In addition, tiremanufacturers have desire improved grip on both on wet and dryconditions, and wear resistance. As such, manufacturers have typicallyturned to a sulfur-vulcanizable diene rubber composition obtained bythermo-mechanical working of a conjugated diene copolymer and anaromatic vinyl compound, and reinforced with special highly dispersibleprecipitated silica. Highly dispersible precipitated silica is made ofspherical primary particles, which are aggregated together. Theseprimary particles typically have a low aspect ratio, generally around 1.

The so called “green tires” have had a significant commercial success inpassenger car market in Europe and more recently in North America.However the development of green tires for trucks has been moredifficult due to a lower wear resistance than conventional truck tirereinforced mainly with carbon black.

Turning to aluminous materials, nano-boehmite particles can be easilydispersed into a nylon polymer matrix due to the high surfacecompatibility between the boehmite material and the highly polar polymermatrix. However, nano-boehmite particles are difficulty to disperse in anon-polar matrix, such a diene rubber composition for a tireformulation. In general, higher aspect ratio nano-boehmite particles aremore difficult to disperse in rubber.

Numerous solutions have been proposed to improve the dispersion ofinorganic nano-particles with high aspect ratio in non polar polymers.For example, organic surface treatment agents that modify the surfacechemistry of the particles to make it more compatible with the polymerhave been proposed. Such an approach, for example, has been used todisperse nano-clay in Nylon or polypropylene using quaternary ammoniumas an organic surface treatment agent. However, even with the organicagents, it is often difficult to achieve desirable dispersion of suchinorganic particulate, especially if the filler loading is high (morethan 10% per volume). Moreover, in the case of tire formulation, anorganic surface treatment may not be desirable. For example, it may bedesirable for the surface of the reinforcing fillers to react with apolysulfurized silane coupling agent during the compounding process, andthus can not be passivated by the organic surface treatment agent.

As such, a dispersible filler and composite material formed thereofwould be desirable.

SUMMARY

In a particular embodiment, a particulate material includes aluminahydrate. The particulate material has a 500 psi Compaction Volume Ratioof at least about 4.0 cc/cc.

In another embodiment, a particulate material comprising metal oxidecoated alumina hydrate. The particulate material has a 500 psiCompaction Volume Ratio of at least about 4.0 cc/cc.

In yet another exemplary embodiment, a particulate material includesalumina hydrate. The particulate material has a Cumulative Pore VolumeRatio of at least about 3.0.

In a further exemplary embodiment, a particulate material includesalumina hydrate. The particulate material has an Hg Cumulative PoreVolume Index of at least about 3.0 cc/cc.

In another exemplary embodiment, a particulate material includes aseeded alumina hydrate. The particulate material has an isoelectricpoint of not greater than about 5.

In a further exemplary embodiment, a method of making a particulatematerial includes adding an inorganic salt comprising an oxidized metalanion to an alumina hydrate suspension. The method further includesadding an acidifying agent to the alumina hydrate suspension, whereby alayer of metal oxide is precipitated onto alumina hydrate particles ofthe alumina hydrate suspension to form a particulate material.

In yet another exemplary embodiment, a method of making a particulatematerial includes adding an inorganic silicate salt to an aluminahydrate suspension. The method further includes adding an acidifyingagent to the alumina hydrate suspension and reacting to precipitate alayer of silica onto alumina hydrate particles in the alumina hydratesuspension to form the particulate material.

In another exemplary embodiment, a particulate material includestransition alumina. The particulate material has an Hg Cumulative PoreVolume Index of at least about 3.0 cc/cc.

In yet another exemplary embodiment, a particulate material includestransition alumina. The particulate material has a 500 psi CompactionVolume Ratio of at least about 4.0 cc/cc.

In a further exemplary embodiment, a particulate material includes alphaalumina. The particulate material has an Hg Cumulative Pore Volume Indexof at least about 3.0 cc/cc.

In another exemplary embodiment, a particulate material includes alphaalumina. The particulate material has a 500 psi Compaction Volume Ratioof at least about 4.0 cc/cc.

In yet another exemplary embodiment, a catalyst includes a particulatematerial and a catalytic agent on the surface of the particulatematerial. The particulate material has a 500 psi Compaction Volume Ratioof at least about 4 cc/cc.

In a further exemplary embodiment, an inkjet paper includes a papersubstrate and a coating disposed on at least one side of the papersubstrate. The coating includes a particulate material having a 500 psiCompaction Volume Ratio of at least about 4.0 cc/cc.

In another exemplary embodiment, a composite material includes a polymermatrix and a particulate material dispersed within the polymer matrix.The particulate material has a 500 psi Compaction Volume Ratio of atleast about 4.0 cc/cc.

In yet another exemplary embodiment, a composite material includes apolymer matrix and an aggregate. The aggregate includes a particle witha geometric aspect ratio of at least about 3.0. Additionally, theaggregate has a Dispersibility Index of at least 94%.

In another exemplary embodiment, a particulate material comprises anaggregate. The aggregate includes a particle with a geometric aspectratio of at least about 3.0. Additionally, the aggregate has aDispersibility Index of at least about 94%.

In a further exemplary embodiment, a particulate material includes ametal oxide coated alumina hydrate. The particulate material has aDispersibility Index of at least about 90%.

In another exemplary embodiment, a method of making an article includesmixing a particulate material with a polymer resin. The particulatematerial comprises alumina hydrate. Further, the particulate materialhas a 500 psi Compaction Volume Ratio of at least about 4.0 cc/cc.

In a further exemplary embodiment, a composite material comprises asilicone matrix and a particulate material dispersed within the siliconematrix. The particulate material includes an alumina hydrate.Additionally, the particulate material has a 500 psi Compaction VolumeRatio of at least about 4.0 cc/cc.

DETAILED DESCRIPTION

In a particular embodiment, a particulate material includes treatedalumina hydrate, such as silica coated alumina hydrate. In an example,the particulate material can have a 500 psi Compaction Volume Ratio (theratio of the volume of the air to the volume of the solid when the solidis compressed at 500 psi) of at least about 4.0 cc/cc, indicating arelatively high porosity and relatively high compaction strength. Inaddition, the particulate material may have an Hg Cumulative Pore VolumeIndex (porosity in the pore size range between 10 and 1000 nm multipliedby the specific density of the particulate material) of at least about3.0 cc/cc. In a particular embodiment, the particulate material includessilica coated alumina hydrate in which the alumina hydrate includesboehmite and the silica coating comprises about 10% to about 50% byweight of the particulate material.

In an exemplary embodiment, a method of manufacturing a treated aluminahydrate material includes reacting an inorganic salt solution (such assodium silicate or sodium tungstate) with an acidifying agent in thepresence of an alumina hydrate particulate, thus precipitating a layerof metal oxide onto the alumina hydrate particulate to form a metaloxide coated alumina hydrate material. Further, the method may includewashing the metal oxide coated alumina hydrate material to remove excesssalts and drying the metal oxide coated alumina hydrate material toobtain a dry particulate material. The metal oxide forming the coatingof the metal oxide coated alumina hydrate may have an iso-electric pointof not greater than about 6.0. In another embodiment, an additive, suchas citric acid, is added to a solution of alumina hydrate particles tolower the iso-electric point of the alumina hydrate particles prior tothe addition of the inorganic salt solution to better control theparticle agglomeration prior to the metal oxide coating.

In a further exemplary embodiment, a composite material includes apolymer matrix and a metal oxide coated alumina hydrate materialdispersed within the polymer matrix. The metal oxide coated aluminahydrate material may have a 500 psi Compaction Volume Ratio of at leastabout 4.0 cc/cc, or an Hg Cumulative Pore Volume Index of at least about3.0 cc/cc, indicating a relatively high porosity and relatively highcompaction strength.

In an additional exemplary embodiment, a method of making an articlecomprises mixing a particulate material with a polymer resin. Theparticulate material includes a metal oxide coated alumina hydrate.Additionally, the method may include mixing a coupling agent with thepolymer. Alternatively, the method may include pre-treating theparticulate material with a coupling agent. Further, the method mayinclude molding the polymer resin and curing the polymer resin.

Alumina Hydrate Particulate

In general, the alumina hydrate particulate includes hydrated aluminaconforming to the formula: Al(OH)_(a)O_(b), where 0≦a≦3 and b=(3−a)/2,with the exception of impurities. In a particular embodiment, 1≦a≦2. Byway of example, when a=0 the formula corresponds to alumina (Al₂O₃). Ingeneral, the alumina hydrate particulate material has a water content ofabout 1% to about 38% by weight, such as about 15% to about 38% watercontent by weight.

In particular, the alumina hydrate particulate may include aluminumhydroxides, such as ATH (aluminum tri-hydroxide), in mineral forms knowncommonly as gibbsite, bayerite, or bauxite, or may include aluminamonohydrate, also referred to as boehmite. Such mineral form aluminumhydroxides may form alumina hydrate particulate material useful informing the particulate or may be used as an aluminous precursor, forfurther processing, such as in a seeded hydrothermal treatment,described in more detail below.

With particular reference to the morphologies of the alumina hydrateparticles, different morphologies are available, such as needle-shaped,ellipsoidal-shaped, and platelet-shaped particles. For example,particles having a needle-shaped morphology may be further characterizedwith reference to a primary aspect ratio defined as the ratio of thelongest dimension to the second longest dimension perpendicular to thelongest dimension and a secondary aspect ratio defined as the ratio ofthe second longest dimension to the third longest dimensionperpendicular to the first and second longest dimensions. The primaryaspect ratio of needle-shape particle is generally greater than 2:1,preferably greater than 3:1, and more preferably greater or equal to6:1. The secondary aspect ratio generally describes the cross-sectionalgeometry of the particles in a plane perpendicular to the longestdimension. The secondary aspect ratio of needle-shaped particles isgenerally not greater than about 3:1, typically not greater than about2:1, or not greater than about 1.5:1, and oftentimes about 1:1.

According to another embodiment, the alumina hydrate particles may beplaty or platelet-shaped particles generally of an elongated structure.However, platelet-shaped particles generally have opposite majorsurfaces, the opposite major surfaces being generally planar andgenerally parallel to each other. In addition, the platelet-shapedparticles may be characterized as having a secondary aspect ratiogreater than that of needle-shaped particles, generally at least about3:1, such as at least about 6:1, or at least about 10:1. Typically, theshortest dimension or edge dimension, perpendicular to the oppositemajor surfaces or faces, is generally less than 50 nanometers, such asless than about 40 nanometers, or less than about 30 nanometers.

According to another embodiment, a cluster of platelet-shaped particlescan generally form an elongated ellipsoidal structure having a primaryaspect ratio described above in connection with the needle-shapedparticles. In addition, the ellipsoidal-shaped cluster may becharacterized as having a secondary aspect ratio not greater than about2:1, not greater than about 1.5:1, or about 1:1.

According to an embodiment, the alumina hydrate particles have ageometric aspect ratio, defined as the ratio of the longest dimension tothe square root of the product of the shorter two orthogonal dimensions,generally at least about 3.0, and, in particular, at least about 4.5,such as at least about 6.0. Generally, needle-shape particles have ahigher geometric aspect ratio than platelet-shaped particles andellipsoidal-shaped particles of comparable size. Typically, thegeometric aspect ratio correlates with dispersion of untreated aluminahydrate particles.

Morphology of the alumina hydrate particulate material may be furtherdefined in terms of particle size and, more particularly, averageparticle size. As used herein, the “average particle size” is used todenote the average longest or length dimension of the alumina hydrateparticles. Generally, the average particle size is not greater thanabout 1000 nanometers, such as about 30 nanometers to about 1000nanometers. For example, the average particle sizes may be not greaterthan about 800 nanometers, not greater than about 500 nanometers, or notgreater than about 300 nanometers. In the context of fine particulatematerial, embodiments have an average particle size not greater than 250nanometers, such as not greater than 225 nanometers. Due to processconstraints of certain embodiments, the smallest average particle sizeis generally at least about 30 nanometers, such as at least about 50nanometers, or at least about 100 nanometers. In particular, the averageparticle size may be about 30 nanometers to about 1000 nanometers, suchas about 50 nanometers to about 250 nanometers, or about 100 nanometersto about 200 nanometers.

Due to the elongated morphology of the particles, conventionalcharacterization technology is generally inadequate to measure averageparticle size, since characterization technology is generally based uponan assumption that the particles are spherical or near-spherical.Accordingly, average particle size is determined by taking multiplerepresentative samples and physically measuring the particle sizes foundin representative samples. Such samples may be taken by variouscharacterization techniques, such as by scanning electron microscopy(SEM). The term average particle size also denotes primary particlesize, related to the individually identifiable particles, whether indispersed, aggregated, or agglomerated forms. The term aggregate denotesa group of primary particles, which are strongly bound together, and theterm agglomerate denotes a group of aggregates that are weakly bondtogether. In general, it is easier to measure the size of the primaryparticles before they are aggregated together. Typically, aggregates andagglomerates have a comparatively larger average size. For example,aggregates may have an average size of about 250 nm to about 2000 nm,such as about 300 nm to about 1000 nm, or even about 300 nm to about 600nm. In another example, agglomerates may have a size greater than about2000 nm, such as greater than about 10 microns, or even as high as 100microns.

In a particular embodiment, when a is approximately one (1) within thegeneral formula: Al(OH)_(a)O_(b), where 0≦a≦3 and b=(3−a)/2, the aluminahydrate material corresponds to boehmite. More generally, the term“boehmite” is used herein to denote alumina hydrates including mineralboehmite, typically being Al₂O₃.H₂O and having a water content on theorder of 15%, as well as pseudo-boehmite, having a water content greaterthan 15%, such as 20% to 38% by weight. As such, the term “boehmite”will be used to denote alumina hydrates having 15% to 38% water content,such as 15% to 30% water content by weight. It is noted that boehmite(including pseudo-boehmite) has a particular and identifiable crystalstructure, and accordingly, a unique X-ray diffraction pattern, and assuch, is distinguished from other aluminous materials including otherhydrated aluminas.

Boehmite may be obtained by processing aluminous minerals, such as analuminous precursor through a seeded processing pathway, to providedesirable morphology and particle characteristics. Alumina hydrateparticles formed through a seeded process are particularly suited forforming treated alumina hydrate agglomerates, as described below. Suchseeded processing advantageously may provide desirable particlemorphologies and the particles formed by such processes may be furthertreated without removing them from solution, such as the solution inwhich they were formed in situ.

Turning to the details of the processes by which the seeded aluminousparticulate material may be manufactured, typically an aluminousmaterial precursor including bauxitic minerals, such as gibbsite andbayerite, are subjected to hydrothermal treatment as generally describedin the commonly owned patent, U.S. Pat. No. 4,797,139. Morespecifically, the particulate material may be formed by combining theprecursor and seeds (having desired crystal phase and composition, suchas boehmite seeds) in suspension, exposing the suspension (alternativelysol or slurry) to heat treatment to cause conversion of the raw materialinto the composition of the seeds (in this case boehmite). The seedsprovide a template for crystal conversion and growth of the precursor.Heating is generally carried out in an autogenous environment, that is,in an autoclave, such that an elevated pressure is generated duringprocessing. The pH of the suspension is generally selected from a valueof less than 7 or greater than 8, and the boehmite seed material has aparticle size finer than about 0.5 microns, preferably less than 100 nm,and even more preferably less than 10 nm. In the case in which the seedsare agglomerated, the seed particles size refers to seed primaryparticles size. Generally, the seed particles are present in an amountgreater than about 1% by weight of the boehmite precursor, typically atleast 2% by weight, such as 2 to 40% by weight, more typically 5 to 15%by weight (calculated as Al₂O₃). Precursor material is typically loadedat a percent solids content of 60% to 98%, preferably 85% to 95%.Alternatively, the total loading of the solid material is about 10% toabout 50%, such as about 15% to about 30%.

Heating is carried out at a temperature greater than about 100° C., suchas greater than about 120° C., or even greater than about 130° C. In anembodiment, the processing temperature is greater than 150° C. Usually,the processing temperature is below about 300° C., such as less thanabout 250° C. Processing is generally carried out in the autoclave at anelevated pressure, such as within a range of about 1×10⁵ newtons/m² toabout 8.5×10⁶ newtons/m². In one example, the pressure is autogenouslygenerated, typically around 2×10⁵ newtons/m².

In the case of relatively impure precursor material, such as bauxite,the material is washed, such as rinsing with de-ionized water, to flushaway impurities such as silicon and titanium hydroxides and otherresidual impurities remaining from the mining processes to sourcebauxite.

The particulate aluminous material may be fabricated with extendedhydrothermal conditions combined with relatively low seeding levels andacidic pH, resulting in preferential growth of boehmite along one axisor two axes. Longer hydrothermal treatment may be used to produce evenlonger and higher aspect ratio of the boehmite particles or largerparticles in general. Time periods typically range from about 1 to 24hours, preferably 1 to 3 hours.

Following heat treatment and crystalline conversion, the liquid contentis generally removed, desirably through a process that limitsagglomeration of the particles of boehmite upon elimination of water,such as freeze drying, spray drying, or other techniques to preventexcess agglomeration. In certain circumstances, ultrafiltrationprocessing or heat treatment to remove the water might be used.Thereafter, the resulting mass may be crushed, such as to 100 mesh, ifdesired. It is noted that the particulate size described hereingenerally describes the single crystallites formed through processing,rather than any aggregates or agglomerates that may remain in certainembodiments.

Alternatively, the particulate aluminous material may be kept insuspension, forming a colloidal suspension. For example, the particulatealuminous material may be maintained in situ sol. In another example,the liquid content in which the particulate aluminous material issuspended may be replaced through washing, liquid-liquid exchange, orother separation techniques that result in the particulate aluminousmaterial remaining in colloidal suspension. In particular, suchcolloidal suspended particulate aluminous materials provide advantageswhen further treated.

Several variables may be modified during the processing of theparticulate material to effect the desired morphology. These variablesnotably include the weight ratio, that is, the ratio of precursor (i.e.,feed stock material) to seed, the particular type or species of acid orbase used during processing (as well as the relative pH level), and thetemperature (which is directly proportional to pressure in an autogenoushydrothermal environment) of the system.

In particular, when the weight ratio is modified while holding the othervariables constant, the shape and size of the particles forming theboehmite particulate material are modified. For example, when processingis carried at 180° C. for two hours in a 2 weight % nitric acidsolution, a 90:10 ATH:boehmite ratio (precursor:seed ratio) formsneedle-shaped particles (ATH being a species of boehmite precursor). Incontrast, when the ATH:boehmite seed ratio is reduced to a value of80:20, the particles become more elliptically shaped. Still further,when the ratio is further reduced to 60:40, the particles becomenear-spherical. Accordingly, most typically the ratio of boehmiteprecursor to boehmite seeds is not less than about 60:40, such as notless than about 70:30 or 80:20. However, to ensure adequate seedinglevels to promote the fine particulate morphology that is desired, theweight ratio of boehmite precursor to boehmite seeds is generally notgreater than about 98:2. Based on the foregoing, an increase in weightratio generally increases aspect ratio, while a decrease in weight ratiogenerally decreased aspect ratio.

Further, when the type of acid or base is modified, holding the othervariables constant, the shape (e.g., aspect ratio) and size of theparticles are affected. For example, when processing is carried out at180° C. for two hours with an ATH:boehmite seed ratio of 90:10 in a 2weight % nitric acid solution, the synthesized particles are generallyneedle-shaped. In contrast, when the acid is substituted with HCl at acontent of 1 weight % or less, the synthesized particles are generallynear spherical. When 2 weight % or higher of HCl is utilized, thesynthesized particles become generally needle-shaped. At 1 weight %formic acid, the synthesized particles are platelet-shaped. Further,with use of a basic solution, such as 1 weight % KOH, the synthesizedparticles are platelet-shaped. When a mixture of acids and bases isutilized, such as 1 weight % KOH and 0.7 weight % nitric acid, themorphology of the synthesized particles is platelet-shaped. Noteworthy,the above weight % values of the acids and bases are based on the solidscontent only of the respective solid suspensions or slurries, and arenot based on the total weight of the slurries.

Suitable acids and bases include mineral acids such as nitric acid,organic acids such as formic acid, halogen acids such as hydrochloricacid, and acidic salts such as aluminum nitrate and magnesium sulfate.Effective bases include, for example, amines including ammonia, alkalihydroxides such as potassium hydroxide, alkaline hydroxides such ascalcium hydroxide, and basic salts.

Still further, when temperature is modified while holding othervariables constant, typically changes are manifested in particle size.For example, when processing is carried out at an ATH:boehmite seedratio of 90:10 in a 2 weight % nitric acid solution at 150° C. for twohours, the crystalline size from XRD (x-ray diffractioncharacterization) was found to be 115 Angstroms. However, at 160° C. thecrystalline size was found to be 143 Angstroms. Accordingly, astemperature is increased, average particle size is also increased,representing a directly proportional relationship between averageparticle size and temperature.

According to embodiments described herein, a relatively powerful andflexible process methodology may be employed to engineer desiredmorphologies into the particulate material. Of particular significance,embodiments utilize seeded processing resulting in a cost-effectiveprocessing route with a high degree of process control which may resultin desired fine average particle sizes as well as controlled particlesize distributions. The combination of (i) identifying and controllingkey variables in the process methodology, such as weight ratio, acid andbase species and temperature, and (ii) seeding-based technology is ofparticular significance, providing repeatable and controllableprocessing of desired particulate material morphologies.

In the context of seeded aluminous particulate material, particularsignificance is attributed to the seeded processing pathway, as not onlydoes seeded processing to form seeded particulate material allow fortightly controlled morphology of the precursor (which is largelypreserved in the final product), but also the seeded processing route isbelieved to manifest desirable physical properties in the final product,including compositional, morphological, and crystalline distinctionsover particulate material formed by conventional, non-seeded processingpathways.

Additional characterization studies were carried out to more preciselyunderstand the effect of seeding on particle morphology. The seededparticles have a nodular structure, in that the particles are ‘bumpy’ or‘knotty’ and have a generally rough outer texture. Furthercharacterization was carried out by TEM analysis to discover that whatappears by SEM to be generally monolithic particles, the particles areactually formed of tight, dense assemblies of platelet particles. Theparticles have a controlled aggregate morphology, in that the aggregatesdisplay a level of uniformity beyond conventional aggregatetechnologies. It is understood that the controlled aggregate structuresform the nodular structure, and are unique to the seeded approachdiscussed above.

It is recognized that non-seeded approaches have been found to formparticulate material, including approaches that decompose raw materialsthrough consumption of an aluminum salt, such as aluminum nitrate oraluminum sulfate. However, these metal salt decomposition approachesform morphologically distinct particulates that are devoid of the seededmorphology, notably lacking the nodular structure. Typical non-seededmorphology has a smooth or hair-like outer surface texture. Examples ofsuch non-seeded approaches include those disclosed in U.S. Pat. No.3,108,888, U.S. Pat. No. 2,915,475, and JP2003-054941.

Treated Alumina Hydrate Particulate

In a particular embodiment, the alumina hydrate particulate may befurther treated, such as by coating the alumina hydrate particulate withan inorganic coating, generally resulting in particle agglomerates ofcoated alumina hydrate particles. In particular, the alumina hydrateparticulate may be coated with a ceramic oxide, such as a metal oxide.For example, the alumina hydrate particulate may be coated with a metaloxide, such as silica, tin oxide, vanadium oxide, tungsten oxide,manganese oxide, antimony oxide, niobium oxide, molybdenum oxide, or anycombination thereof. In an exemplary embodiment, the metal oxide may beselected from metal oxides having a iso-electric point not greater thanabout 6.0, such as not greater than about 5.0, or not greater than about3.0. In addition, the metal oxide may have a basic precursor, forexample, including a metal that forms an oxidized water soluble anion ofsodium or potassium. Further, the metal oxide may be substantiallyinsoluble in water. In a particular example, the coating may be formedusing a colloidal aluminous suspension, for example, including a seededaluminous material. In an exemplary embodiment, the alumina hydrateparticulate may be coated with silica.

Turning to the process by which a metal oxide coated alumina hydratematerial may be manufactured, typically the alumina hydrate particulateis provided in a suspension (alternatively sol or slurry). Inparticular, the alumina hydrate particulate is a seeded alumina hydrateparticulate that is in suspension, such as suspended in a portion of thesolution in which it was formed in situ. The suspension may be dilutedwith deionized water to form a suspension with about 1 wt % to about 10wt % alumina hydrate particulate based on the total weight of thesuspension. In an alternative example, the alumina hydrate particulatemay be provided in a dry form and added to deionized water (di-H₂O) toform the suspension having at least about 20 g/l alumina hydrateparticulate, such as at least about 30 g/l alumina hydrate particulate,or even at least about 40 g/l alumina hydrate particulate. Further, thesuspension may be heated to above 50° C., such as between about 50° C.and about 99° C., or even between about 80° C. and about 90° C.,particularly between about 80° C. and about 85° C., and may be stirredat a low speed. Generally, the resulting suspension has a pH not greaterthan about 6.

Optionally, the surfaces of the alumina hydrate particles may bepre-treated, for example, to lower the iso-electric point of the aluminahydrate particles. In an exemplary embodiment, a surface modifyingagent, such as a weak acid, may be added to the alumina hydratesuspension. For example, the surface modifying agent may include citricacid or Darvan C (Ammonium polymethacrylate, PMAA). In particular, asurface modifying agent is an agent that can reduce the iso-electricpoint of the alumina hydrate particles to less than 9.0. For example,the surface modifying agent may reduce the iso-electric point of thealumina hydrate particles to less than about 6.0, such as not greaterthan about 5.0. In an example, the surface modifying agent may be addedto the alumina hydrate suspension in an amount between 1% and 10% byweight of the alumina hydrate particulate. In particular, the surfacemodifying agent may be added piecemeal. For example, about 55% of theallotted citric acid may be added to the alumina hydrate suspension andthe suspension may be mixed, such as for at least 15 minutes, to ensurethe citric acid is well dispersed in the alumina hydrate suspension.Subsequently, the remainder of the citric acid may be added to thesuspension. In another example, citric acid may be divided into 3 to 5parts and added one by one, stirring for at least about 5 minutes aftereach part is added. In each case, the suspension may be stirred at aspeed adjusted for the viscosity of the suspension. For example, thesuspension may be stirred at a greater speed to lower the viscosity anddisperse the surface modifying agent.

In a further example, the pH of the suspension may be increased prior tothe addition of the inorganic salt, such as through addition of a base,e.g., sodium hydroxide. For example, the pH may be adjusted to at leastabout 5, such as about 5 to about 7.

To facilitate coating with a metal oxide such as silica, a quantity ofinorganic salt including an oxidized metal anion (e.g., an inorganicsilicate salt) may be added to the suspension such that an amount ofmetal oxide precipitated to coat the alumina hydrate particulate isabout 10% to about 50% by weight of the resulting treated aluminahydrate material, such as about 15% to about 40%, for example, about 20%to about 30% by weight. In an exemplary embodiment, the inorganicsilicate salt may be a dilute sodium silicate solution. Alternatively,the inorganic silicate salt may include a Group I metal silicate, suchas potassium silicate. In an example, the inorganic silicate may beadded slowly until the pH of the alumina hydrate suspension increases,such as to between about 6.0 and 8.0, such as between about 7.0 and 8.0.In another example, the inorganic silicate is added until the pH isincreased to a range of about 8.0 to about 10.0, such as about 8.5 toabout 9.5. Once the pH has increased to the desired range, the remainderof the inorganic silicate may be added in conjunction with an acidifyingagent, such as sulfuric acid, to maintain the desired pH. The aluminahydrate suspension may be stirred for at least 10 minutes, such as atleast 20 minutes, or even about 30 minutes.

In an exemplary embodiment, an acidifying agent is added to reduce thepH of the alumina hydrate solution to a range of about 3.0 to about 8.0,such as about 4.0 to about 7.0, or about 5.0 to about 6.0. Theacidifying agent may be an acid, such as an inorganic acid or an organicacid. In an example, an inorganic acid includes sulfuric acid,hydrochloric acid, nitric acid, phosphoric acid, or any combinationthereof. In another example, the organic acid may include formic acid.In a particular example, the acidifying agent may be sulfuric acid. As aresult of the process, the treated alumina hydrate material forms smallaggregates of coated alumina hydrate particles.

In addition, the treated alumina hydrate material optionally may bewashed to remove salts. For example, the suspension may be diluted withdi-H₂O, mixed, and allowed to settle. The supernatant may be removed andthe process (diluting, mixing, removing supernatant) may be repeateduntil at least about 90% of the estimate ions have been removed. Inanother example, the treated alumina hydrate material may be washed bycentrifugation or may be treated via ion exchange.

In an exemplary embodiment, the liquid content is generally removed,desirably through a process that limits further agglomeration of thetreated alumina hydrate material upon elimination of water, such asfreeze drying, spray drying, or other techniques adapted to preventexcess agglomeration. In certain circumstances, ultrafiltrationprocessing or heat treatment to remove the water might be used.Thereafter, the resulting mass may be crushed, such as to 100 mesh, ifdesired.

While the treated alumina hydrate material is desirably used in itsboehmite form, the material may be heat treated to alter the crystallinestructure of the alumina hydrate portion of the treated material. In anexemplary embodiment, the treated alumina hydrate material is heattreated by calcination at a temperature sufficient to causetransformation into a transitional phase alumina, or a combination oftransitional phases. Typically, calcination or heat treatment is carriedout at a temperature greater than about 250° C., but lower than 1100° C.At temperatures less than 250° C., transformation into the lowesttemperature form of transitional alumina, gamma alumina, typically willnot take place. According to certain embodiments, calcination is carriedout at a temperature greater than 400° C., such as not less than about450° C. The maximum calcination temperature may be less than 1100° C. or1050° C., these upper temperatures usually resulting in a substantialproportion of theta phase alumina, the highest temperature form oftransitional alumina.

At temperatures greater than 1100° C., typically the precursor willtransform into the alpha phase. Contrary to untreated boehmite material,a metal oxide coated alumina hydrate material may be heated at hightemperature without loosing its nanostructure, as a result of the metaloxide amorphous coating which may prevent alumina crystal growth duringthe calcinations process.

In another embodiment, the treated alumina hydrate material is calcinedat a temperature lower than 950° C., such as within a range of 750° C.to 950° C. to form a substantial content of delta alumina. According toparticular embodiments, calcination is carried out at a temperature lessthan about 800° C., such as less than about 775° C. or 750° C. to effecttransformation into a predominant gamma phase.

According to an embodiment, the treated alumina hydrate material has ahigh pore volume. Pore volume may be measured in several ways, includingHg porosimetry and BET methods. The Hg porosimetry is measured inaccordance to DIN 66 133. Hg porosimetry results may be used todetermine an Hg Cumulative Pore Volume, the total volume of the poresless than about 300 nm. In an exemplary embodiment, the Hg CumulativePore Volume of the treated alumina hydrate material is generally atleast about 1.50 cc/g, and in particular at least about 1.65 cc/g, suchas at least about 1.75 cc/g.

In addition, Hg porosimetry results may be used to determine a HgCumulative Pore Volume Index. The Hg Cumulative Pore Volume Index is thetotal volume of the pores between 10 nm and 1000 nm measured in cc/gmultiplied by the specific density of the particulate material (e.g.,2.1 g/cc for HD silica, 2.9 g/cc for alumina hydrate, 2.7 g/cc fortreated alumina hydrate with 25 wt % silica, and 2.78 g/cc for treatedalumina hydrate with 15 wt % silica). In an exemplary embodiment, the HgCumulative Pore Volume Index of the treated alumina hydrate material isgenerally at least about 3.0 cc/cc, and in particular, at least about4.0 cc/cc, such as at least about 6.0 cc/cc, or even at least about 6.5cc/cc.

BET pore volume may be determined according to ISO 5794. BET pore volumeresults may be used to determine a BET Cumulative Pore Volume, the totalvolume of the pores less than about 300 nm. The BET Cumulative PoreVolume of the treated alumina hydrate material may be generally at leastabout 0.3 cc/g.

Additionally, a Cumulative Pore Volume Ratio is the ratio between the HgCumulative Pore Volume and the BET Cumulative Pore Volume. In anexemplary embodiment, the Cumulative Pore Volume Ratio of the treatedalumina hydrate material is generally at least about 3.0, and inparticular, at least about 4.0, such as at least about 5.0.

Further, a BET Surface Area may be determined according to ISO 5794. Thevalue of the BET surface area measured in m²/g is multiplied by thespecific density of the particulate material to obtain a value in m²/cc.For example, the BET Surface Area of the treated alumina hydratematerial may be generally at least about 150 m²/cc, such as at leastabout 300 m²/cc.

Additionally, a pre-compression loose packed density (LPD) may bedefined as the amount, in grams, of aggregate that fills, withoutcompression, a cavity divided by the volume of the cavity and dividedagain by the density of the material (e.g., 2.1 g/cc for HD silica, 2.9g/cc for alumina hydrate, 2.7 g/cc for treated alumina hydrate with 25wt % silica, and 2.78 g/cc for treated alumina hydrate with 15 wt %silica). For example, the LPD of the treated alumina hydrate materialmay be generally not greater than about 0.06 cc/cc, and in particular,not greater than about 0.05 cc/cc, such as not greater than about 0.04cc/cc. In another embodiment, the treated alumina hydrate material ispre-compacted to achieve a post compaction LPD of at least about 0.10cc/cc, such as at least about 0.13 cc/cc to facilitate the shipping andthe handling of the particulate material.

According to an embodiment, the treated alumina hydrate material has ahigh resistance to compression. In an exemplary test, the material isplaced within a cavity and compressed. A volume of the solid (cc) isdetermined by taking the weight of the material (g) and dividing by thedensity of the material (e.g., 2.1 g/cc for HD silica, 2.9 g/cc foralumina hydrate, 2.7 g/cc for treated alumina hydrate with 25 wt %silica, and 2.78 g/cc for treated alumina hydrate with 15 wt % silica).A volume of the air (cc) is the difference between the volume of thecavity (cc) and the volume of the solid (cc). A 100 psi CompactionVolume Ratio is defined as the ratio of the volume of the air to thevolume of the solid when the solid is compressed at 100 psi. In anexemplary embodiment, the 100 psi Compaction Volume Ratio of the treatedalumina hydrate material may be generally at least about 6.0 cc/cc, andin particular, at least about 8.0 cc/cc, such as at least about 10.0cc/cc.

Additionally, a 500 psi Compaction Volume Ratio is defined as the ratioof the volume of the air to the volume of the solid when the solid iscompressed at 500 psi. In an exemplary embodiment, the 500 psiCompaction Volume Ratio of the treated alumina hydrate material may begenerally at least about 4.0 cc/cc, and in particular, at least about5.0 cc/cc, such as at least about 6.0 cc/cc.

An isoelectric point (IEP) may be determined by measuring a charge ofthe material as a function of pH. In particulate, the IEP is the pH atwhich the net charge of the material is about 0. In an example, the IEPof the treated alumina hydrate material may be not greater than about5.0, such as not greater than about 2.0, and in particular, not greaterthan about 1.5.

Particular embodiments of the treated alumina hydrate material mayexhibit improved properties that provide advantages in particularapplications. For example, particular embodiments of the treated aluminahydrate material may exhibit a high Compaction Volume Ratio, indicatingaggregate strength, and a high Cumulative Pore Volume Index, indicatinga high number of pores less than 1 micron in size. Such aggregatestrength and porosity, for example, may lead to improved dispersion inpolymer matrices. In addition, the surface properties of embodiments ofthe treated alumina hydrate particulate may lead to improved dispersion,improved absorption of liquids, and improved receptiveness to coatings.

Dispersing in a Polymer

In a particular embodiment, the silica coated alumina hydrate materialmay be dispersed within a polymer matrix. In a particular embodiment,the polymer matrix includes an elastomeric polymer. Elastomeric polymersare those polymers that when moderately deformed (stretched, twisted,spindled, mutilated, etc.), typically spring back into their originalshape. One exemplary elastomer is lightly-crosslinked natural rubber.Another exemplary elastomeric polymer includes polyolefin, polyamide,polyurethane, polystyrene, diene, silicone, fluoroelastomer, andcopolymers, block copolymers, or blends thereof. An exemplary siliconemay include liquid silicone rubber (LSR) or high consistency rubber(HCR). Specific polymers that may be formulated as elastomeric materialsinclude acrylonitrile butadiene styrene (ABS), ethylene propylene dienemonomer rubber (EPDM), fluoroelastomer, polycaprolactam (nylon 6),nitrile butadiene rubber (NBR), or any combination thereof.

In a particular embodiment, the elastomeric polymer includes a dieneelastomer. Diene elastomer or rubber means an elastomer resulting atleast in part (i.e., a homopolymer or a copolymer) from diene monomers(monomers bearing two double carbon-carbon bonds, whether conjugated ornot).

Exemplary diene elastomers include: (a) homopolymer obtained bypolymerisation of a conjugated diene monomer having 4 to 12 carbonatoms; (b) copolymer obtained by copolymerisation of one or more dienesconjugated together or with one or more vinyl-aromatic compounds having8 to 20 carbon atoms; (c) ternary copolymer obtained by copolymerisationof ethylene, of an alpha-olefin having 3 to 6 carbon atoms with anon-conjugated diene monomer having 6 to 12 carbon atoms, such as, forexample, the elastomers obtained from ethylene, from propylene with anon-conjugated diene monomer of the aforementioned type, such as inparticular 1,4-hexadiene, ethylidene norbornene or dicyclopentadiene;and (d) copolymer of isobutene and isoprene (butyl rubber), and also thehalogenated, in particular chlorinated or brominated, versions of thistype of copolymer.

Unsaturated diene elastomers, in particular those of type (a) or (b)above, are particularly adaptable for use in tire tread. An exemplaryconjugated diene includes 1,3-butadiene, 2-methyl-1,3-butadiene,2,3-di(C₁-C₅ alkyl)-1,3-butadienes such as, for instance,2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene,2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene,aryl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene, or any combinationthereof. An exemplary vinyl-aromatic compound includes, for example,styrene, ortho-, meta- and para-methylstyrene, the commercial mixture“vinyltoluene”, para-tert butylstyrene, methoxystyrenes, chlorostyrenes,vinylmesitylene, divinylbenzene, vinylnaphthalene, or any combinationthereof.

In another example, the diene elastomer of the composition may beselected from the group of highly unsaturated diene elastomers, whichconsists of polybutadienes (BR), synthetic polyisoprenes (IR), naturalrubber (NR), butadiene-styrene copolymers (SBR), butadiene-isoprenecopolymers (BIR), butadiene-acrylonitrile copolymers (NBR),isoprene-styrene copolymers (SIR), butadiene-styrene-isoprene copolymers(SBIR), or mixtures of these elastomers.

In an exemplary embodiment, the treated alumina hydrate material and thepolymer matrix are combined and mixed to sufficiently disperse thetreated alumina hydrate material. For example, the polymer matrix may bemixed for at least about 2 minutes. A coupling agent may be added to thepolymer matrix. Alternatively, the treated alumina hydrate material maybe further pretreated with the coupling agent.

Typically, a coupling agent includes at least one rubber reactivefunctional group that is reactive with the elastomer and includes atleast one filler reactive functional group that is reactive with thefiller. Generally, the coupling agent may establish a chemical orphysical connection between the reinforcing filler and the elastomer. Inaddition, the coupling agent may facilitate dispersion of the fillerwithin the elastomer. In a particular example, the coupling agentincludes a silane-based filler reactive functional group.

In an exemplary embodiment, the polymer matrix may be cured. Theelastomeric polymer may be cured through crosslinking, such as throughvulcanization. In a particular embodiment, the elastomeric polymer iscurable using sulfur-based agents, such as at least one of elementalsulfur, polysulfide, mercaptan, or any combination thereof. In anotherembodiment, the elastomer is curable using peroxide-based agents, suchas metallic peroxides, organic peroxides, or any combination thereof. Inanother embodiment, the elastomer is curable using a platinum catalyst.In a further example, the formulation is curable using amine-basedagents.

In particular, composite materials including a polymer and the treatedalumina hydrate material may include the treated alumina hydratematerial at loadings of about 20% to about 400%, such as about 30% toabout 200%, based on the weight of the polymer. In general, compositematerials including the treated alumina hydrate material may provideimproved properties relative to composites including highly dispersiblesilica at lower total filler loading.

The properties of the resulting composite material may be influenced byhow well the particulate material disperses in the polymer matrix. Forexample, dispersion of agglomerates in a polymer may be measuredaccording to ASTM 2663. A Dispersibility Index may be defined as thedispersion of the agglomerates within a typical passenger tireformulation following the procedure described in more detail in Example4. In an embodiment, the Dispersibility Index of the treated aluminahydrate material may be at least about 90%, and in particular, at leastabout 94%, such as at least about 95%.

Particular embodiments of a composite material including treated aluminahydrate may advantageously be used in tires. In particular, embodimentsof the composite material provide improved mechanical properties andwear resistance. Such wear resistance of a composite material isespecially useful in high severity applications, such as truck tires.Improvement in wear resistance also can be useful for passenger cartires to improve service life, or reduce tread thickness to maintain thesame service life while further reducing rolling resistance.

Other Uses

In a particular embodiment, the treated alumina hydrate material may bedispersed within an inkjet paper coating. The inkjet paper coating mayinclude polyvinyl alcohols, polymers, or appropriate combinationsthereof. In a particular embodiment, the coating may be disposed on atleast one side of a paper substrate. The inkjet paper coating mayprovide a high ink absorbing speed, i.e. fast drying times, and imagepermanence without swelling the paper substrate. Particular embodimentsof the treated alumina hydrate material advantageously may absorb inkinto a highly porous structure. In particular, treated alumina hydrateparticulates exhibiting a high Hg Cumulative Pore Volume Index mayadvantageously prevent bleeding of ink.

In another embodiment, the invention is directed to a catalystcomprising a treated alumina hydrate material or calcined derivativesthereof and a catalytic agent disposed on the surface of the material.An example of a catalytic agent includes a metal, such as platinum,gold, silver, palladium, or any combination thereof. In another example,the catalytic agent may include a metal oxide or an adsorbed ion. Inparticular embodiments, treated alumina hydrate particulate may exhibitdesirable durability in processes that place mechanical stress oncatalytic particles. Such durability may be attributable to highCompaction Volume Ratios.

Catalytic materials may advantageously include anisotropic aluminamaterials, including untreated or treated alumina hydrate or calcinedderivatives thereof. In particular, metal oxide coated alumina hydratesand derivatives thereof may form catalytic support materials thatexhibit advantageous porosity and mechanical properties.

EXAMPLES Example 1

Comparative samples are formed from commercially available aluminahydrate particulate and silica. These comparative samples are tested forporosity, surface area, and compression strength as illustrated inExample 3 and compared with treated alumina hydrate samples.

For example, an aqueous solution of an alumina hydrate (CAM 9010-1,available from Saint-Gobain Ceramics and Plastics Corporation), having arod shape and a geometric aspect ratio around three, is freeze-dried andcrushed to prepare Sample 1.

In another example, an aqueous solution of an alumina hydrate in theform of platelets (CAM 9080, available from Saint-Gobain Ceramics andPlastics Corporation) is freeze-dried and the powder crushed to prepareSample 2.

In a further example, an aqueous solution of an alumina hydrate (CAM9010-2, available from Saint-Gobain Ceramics and Plastics Corporation),having a rod shape and a geometric aspect ratio in the range of 6-10, isfreeze-dried and crushed to prepare Sample 3.

In an additional example, an aqueous solution of an alumina hydrate (CAM9010-2, available from Saint-Gobain Ceramics and Plastics Corporation),having a rod shape and a geometric aspect ratio in the range of 6-10,from Sample 3 is mixed with water to lower its viscosity. The solutionis stirred as the ion exchange resin (Dowex Marathon A OH form) isadded, until a pH of around 5 is reached. The mixture is filtered toremove the resin beads. The resulting solution is freeze-dried andcrushed to prepare Sample 4.

Sample 5 is derived from a commercially available highly dispersibleprecipitated silica (Tixosil 68, available from Rhodia).

Sample 6 is derived from a commercially available highly dispersibleprecipitated silica (Tixosil 43, available from Rhodia).

Sample 7 is derived from a commercially available highly dispersibleprecipitated silica (Ultrasil 7000, available from Degussa).

Example 2

In addition, samples are prepared of treated alumina hydrate materialfor testing in comparison to the samples of Example 1.

For example, Sample 8 is prepared from an alumina hydrate suspension(CAM 9010-2, available from Saint-Gobain Ceramics and PlasticsCorporation having a rod shape and a geometric aspect ratio in the rangeof 6-10) that has been treated with an ion exchange resin (proceduresimilar to Sample 4). The alumina hydrate suspension is diluted to 5 wt% with di-H2O in a 2 liters stainless steel reaction vessel. Thesuspension is stirred, preferably around 200 rpm, and heated to 85° C.An amount of citric acid equal to about 5.2% of the weight of thealumina hydride particles in the solution is added to lower theisoelectric point of the alumina hydride particles. First, about 55% ofthe citric acid is added, followed by 15 minutes of stirring before theremaining amount of citric acid is added. The stirring speed is adjustedto ensure the citric acid is well dispersed. (Prior its use citric acidis partially neutralized with NaOH to adjust its ph at approximately 5.)

An amount of sodium silicate is added such that the weight of silicaprecipitated is in the range 23-28 wt % of the total weight of theagglomerated solids, and preferably equal to approximately 25 wt %. Adiluted solution of sodium silicate (1 volume of sodium silicate and 1volume di-H2O) is added slowly to the mixture until a pH 9-9.5 isreached. Sulfuric acid is added simultaneously to the remaining sodiumsilicate to maintain the pH in the reaction vessel approximately between8.5 and 9.5, and preferably approximately between 9 and 9.5. After theadditions, the suspension is stirred for 30 minutes, the stirring speedbeing in the range 800-1600 rpm, and preferably around 1200 rpm. Thetemperature is around 81-82° C. Sulfuric acid is added to the suspensionto drop the pH below 6, and preferably between 5 and 6.

The suspension is mixed with di-H₂O and allowed to settle. Thesupernatant is removed and the process repeated until at least 90% ofthe estimated ions in solution are removed. The suspension isfreeze-dried and crushed to obtain Sample 8.

Sample 9 is prepared in a similar manner to that described in relationto Sample 8 using an alumina hydrate suspension (CAM 9010-2, availablefrom Saint-Gobain Ceramics and Plastics Corporation having a rod shapeand a geometric aspect ratio in the range of 6-10), which is not treatedwith the ion exchange resin contrary to Sample 8.

After the nano-boehmite dispersion is introduced in the reaction vesseland diluted with di-H2O to a concentration of 5 wt %, the pH of thesolution is adjusted to approximately 5 with sodium hydroxide.

Sample 10 is prepared in a similar manner to that described in relationto Sample 8, except the alumina hydrate suspension is diluted to a 1.5wt % concentration.

Sample 11 is prepared in a similar manner to that described in relationto Sample 8, except the alumina hydrate is diluted to 5 wt % with asolution of citric acid such that the amount of citric acid is about5.2% of the weight of the alumina hydrate.

Sample 12 is prepared in a similar manner to that described in relationto Sample 8, except five equal amounts of citric acid are added to thesuspension. The solution is stirred for five minutes after each of thefirst four additions, and ten minutes after the last addition.Additionally, the sulfuric acid is diluted with di-H2O (one partsulfuric acid to four parts di-H2O) prior to addition to the suspension.

Sample 13 is prepared in a similar manner to that described in relationto Sample 8, except the suspension of alumina hydrate is not treatedwith the ions exchange resin, the reaction is performed without citricacid, and sodium hydroxide is used to increase the pH to a value between6 and 7 prior to the addition of sodium silicate.

Sample 14 is prepared in a similar manner to that described in relationto Sample 8, except the suspension of alumina hydrate is not treatedwith the ions exchange resin, the reaction is performed without thecitric acid, the pH is adjusted to about 6 with sodium hydroxide priorto the addition of the sodium silicate solution, and the pH ismaintained at a pH of about 7 during the addition of the sodium silicatesolution.

Sample 15 is prepared in a similar manner to that described in relationto Sample 8, except the suspension of alumina hydrate is not treatedwith the ions exchange resin, the pH is adjusted to about 5 with sodiumhydroxide after the dilution to 5 wt % alumina hydrate, the citric acidis diluted with di-H2O and the pH of the citric acid solution isadjusted to about 5 to 5.5 with NaOH. The citric acid solution is addedto the alumina hydrate suspension in five parts, and 15 wt % of sodiumsilicate is added after the pH of the alumina hydrate suspension wasbetween about 6 to 7.

Example 3

The samples are tested for pore volume, packed density, and volume undercompression. In particular, the samples are tested for compaction volumeratio at 100 psi and 500 psi, Hg Cumulative Pore Volume Index, Hgcumulative pore volume, BET cumulative pore volume, BET surface area,loose packed density (LPD), and isoelectric point.

For example, the volume of the solid (cc) is defined as the weight ofthe powder (g) divided by the density (e.g., 2.1 g/cc for HD silica and2.9 g/cc for alumina hydrate). The volume of the air (cc) is defined asthe difference between the volume of the cavity (cc) and the volume ofthe solid (cc). In an example, the 100 psi Compaction Volume Ratio isdefined as the ratio of the volume of the air to the volume of the solidwhen the solid is compressed at 100 psi, and the 500 psi CompactionVolume Ratio is defined as the ratio of the volume of the air to thevolume of the solid when the solid is compressed at 500 psi.

TABLE 1 Compaction Performance of Particulate Materials 100 psi 500 psiSample Compaction Volume Ratio Compaction Volume Ratio reference (cc/cc)(cc/cc) Sample 1 2.8 2.2 Sample 2 2.9 2.2 Sample 3 3.2 2.6 Sample 4 2.92.3 Sample 5 6.2 4.7 Sample 6 6.6 4.6 Sample 7 4.9 4.0 Sample 8 9.6 5.8Sample 9 9.6 5.9 Sample 10 10.5 6.9 Sample 11 9.7 6.1 Sample 12 10.6 6.2Sample 13 9.3 5.4 Sample 14 8.7 5.0 Sample 15 8.4 5.2

It is believed that higher Compaction Volume Ratios influence dispersionof the particulate solids. Each of the treated alumina hydrate samples(Samples 8-15) exhibits increased 100 psi Compaction Volume Ratio and500 psi Compaction Volume Ratio. In addition to being higher than theRatios for untreated alumina hydrate samples (Samples 1-4), the Ratiosfor Sample 8-15 also were higher than traditionally used silicas and thenewer highly dispersible precipitated silica (Samples 5-7).

Pore volume also may influence dispersibility of an agglomeratedparticulate. As such, the samples are tested using both Hg and BETtechniques. The Hg Cumulative Pore Volume is defined as the total volumeof the pores less than about 300 nm as determined by Hg porosimetry. HgCumulative Pore Volume Index is defined as the total volume of the poresbetween 10 nm and 1000 nm as determined by Hg porosimetry relative tothe density of the material. The BET Cumulative Pore Volume is definedas the total volume of the pores less than about 300 nm as determined byBET techniques. The Cumulative Pore Volume Ratio is the ratio betweenthe Hg Cumulative Pore Volume and the BET Cumulative Pore Volume.

TABLE 2 Cumulative Pore Volume for Particulate Samples Hg Hg BETCumulative Cumulative Cumulative Cumulative Pore Sample Pore Volume PoreVolume Pore Volume Volume Reference Index (cc/cc) (cc/g) (cc/g) RatioSample 2 1.67 0.57 0.51 1.12 Sample 3 1.31 0.46 0.51 0.90 Sample 5 3.601.57 0.70 2.24 Sample 6 5.10 1.99 1.04 1.91 Sample 7 3.61 1.59 0.67 2.37Sample 9 5.89 1.53 0.34 4.50 Sample 12 6.72 1.80 0.30 6.00 Sample 136.97 1.82 TBD TBD Sample 14 5.57 2.42 TBD TBD Sample 15 7.17 1.90 TBDTBD

Based on the Hg Cumulative Pore Volume Index, the treated aluminahydrate samples (Samples 9 and 12) appear to have comparable or higherporosities than the untreated alumina hydrate (Samples 2 and 3) and thesilica samples (Samples 5-7). In particular, the treated alumina hydratesamples (Samples 9 and 12) have comparable or higher porosity relativeto Tixosil 43 (Sample 6) despite having similar loose packed density.

For pore sizes less than 0.3 microns, the treated alumina hydratesamples (Samples 9 and 12) have comparable values to other samples.However, the Cumulative Pore Volume Ratio for the treated aluminahydrate samples (Samples 9 and 12) are significantly greater than othersamples, which may be useful in some applications. The Sample 14 has ahigher Hg Cumulative Pore Volume (for pore size lower than 0.3 microns).This may be interesting for some applications.

TABLE 3 BET Surface Area (m²/cc) of Particulate Samples Sample referenceBET surface area (m²/cc) Sample 3 365 Sample 5 330 Sample 6 552 Sample 7443 Sample 8 375 Sample 9 327 Sample 10 448 Sample 11 386 Sample 12 354Sample 13 373 Sample 14 467 Sample 15 392

The BET Surface Area is the surface area adjusted for density. Ingeneral, the adjusted BET Surface Areas of the treated alumina hydratesamples (Samples 9-12) are similar or slightly higher than the valuesfor untreated alumina hydrate (Sample 3). In particular, those samplesthat are washed following treatment exhibit high surface area.

TABLE 4 Loose packed Density (LPD) of Particulate Samples Formulationreference LPD (cc/cc) Sample 2 0.148 Sample 3 0.179 Sample 5 0.114Sample 6 0.043 Sample 7 0.129 Sample 8 0.037 Sample 9 0.033 Sample 100.052 Sample 11 0.041 Sample 12 0.033 Sample 13 0.028 Sample 14 0.039Sample 15 0.043

The LPD of the treated alumina hydrate samples (Samples 8-15) aresignificantly lower than the untreated alumina hydrate samples (Samples2 and 3). Such a reduction in LPD may indicate a more open agglomeratestructure in the treated alumina hydrate samples, which may lead toimproved dispersion in polymeric materials. While the LPD values aboveare pre-compression, the particulate material can also be compacted tofacilitate handling and shipping, altering the LPD.

TABLE 5 Isoelectric Point of Particulate Samples Formulation referenceIEP Sample 3 9.5 Sample 8 1.4 Sample 11 1.4 Sample 14 1.5

As illustrated in Table 5, the treated alumina hydrate samples (Samples8 and 11) exhibit lower IEP than the untreated sample (Sample 3), whichmay indicate significant coverage by the silica coating.

Example 4

Sample compounds are prepared using elastomeric resins and particulatesamples.

For example, Compound 1 is prepared based on a typical formulation for acarbon black and silica filled passenger tire. A Brabender PL2000 sizemixer with a B350 mixing head with Banbury type rotors is used toperform the compounding. The mixing chamber has a volume of about 380 mLand is used to a fill factor of 0.7 (266 mL). The circulating oil isheated to approximately 60° C. using a rotor speed of 80 rpm. To themixer, a first half of a polymer mixture is added.

The polymer mixture includes 103 pph of VSL 5025 (from Bayer AG), 25 pphof CB 24 (from Bayer AG), 7 pph of N220 (from Degussa). A filler derivedfrom Sample 1 is added to the mixer. Between 68 and 95 pph, depending onthe density of the filler so as to include the same volume of filler, isadded to the polymer mixture during mixing. The quantity in grams can bedetermined by multiplying the amounts by a coefficient around 1.35.Subsequently, the remaining polymer is added to the mixer.

After blending for 2 minutes, 5.44 pph of Si 69 (from Degussa), 6 pph ofSunpar 2280 Oil, 1 pph Flectol H, 1 pph Nanox ZA, and 1.5 pph SunproofImproved Wax (Uniroyal Chemical Co.) are added. The mixture ismaintained at 140° C. for 3 minutes then spread on a sheet to cool.

Sulfur and a vulcanization accelerator are added to the mix on a 2-rollmill at about 30° C. For example, between 217.0 pph and 244.9 pph of thecomposite material, depending on the amount of filler added, is combinedwith 2.5 pph of zinc oxide, 3 pph of steric acid, 1.4 pph of Sulfur, 1.8phh of CBS (from Bayer AG), 1.6 pph of DPG (from Bayer AG), and 0.2 pphof Tetrabenzylthiuram disulfide (TBzTD) are combined on a 2-roll mill atabout 30° C.

Compound 2 is prepared as described in relation to Compound 1, exceptthe filler is derived from the Sample 3 particulate.

Compound 3 is prepared as described in relation to Compound 1, exceptthe filler is derived from the Sample 2 particulate.

Compound 4 is prepared as described in relation to Compound 1, exceptthe filler is derived from the Sample 7 particulate.

Compound 5 is prepared as described in relation to Compound 1, exceptthe filler is derived from the Sample 9 particulate.

Compound 6 is prepared as in described in relation to Compound 1, exceptthe filler is derived from the Sample 12 particulate.

The dispersibility of the different compounds is measured using adisperGRADER in accordance with ISO 11345 Method B test. This testrelies on optical microscopy of image analysis to evaluate thepercentage of filler dispersion: 0% is indicative of a very poordispersion, and 100% of a relatively perfect dispersion. Based on thedata collected for precipitated silica, a filler-dispersion of at leastapproximately 90% may achieve desirable abrasion resistance. TheDispersibility Index of a sample is defined as the dispergrader valueassociated with dispersion in the passenger tire formulation describedin relation to the compounds above.

TABLE 6 Dispersibility Index of Particulate Material Compound(Particulate Sample) Dispersibility Index Compound 1 (CAM 9010-1)  6%Compound 2 (CAM 9010-2)  0% Compound 3 (CAM 9080) 49% Compound 4(Ultrasil 7000) 93% Compound 5 (Sample 9) 89% Compound 6 (Sample 12) 97%

As illustrated, the compounds formed from the treated alumina hydratesamples (Compounds 5 and 6) exhibit high dispersion, having aDispersibility Index of at least about 89%. In particular, Compound 6exhibits a Dispersibility Index greater than that of the silica filledcompound (Compound 4). Such improved dispersibility may lead to improvedproperties, such as wear resistance.

Note that not all of the activities described above in the generaldescription or the examples are required, that a portion of a specificactivity may not be required, and that one or more further activitiesmay be performed in addition to those described. Still further, theorder in which activities are listed are not necessarily the order inwhich they are performed.

In the foregoing specification, the concepts have been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the invention as set forth in theclaims below. Accordingly, the specification and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope ofinvention.

As used herein, the terms “comprises,” “comprising,” “includes,““including,““has, ““having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of features is notnecessarily limited only to those features but may include otherfeatures not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive- or and not to an exclusive- or. Forexample, a condition A or B is satisfied by any one of the following: Ais true (or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

Also, the use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims.

After reading the specification, skilled artisans will appreciated thatcertain features are, for clarity, described herein in the context ofseparate embodiments, may also be provided in combination in a singleembodiment. Conversely, various features that are, for brevity,described in the context of a single embodiment, may also be providedseparately or in any subcombination. Further, references to valuesstated in ranges include each and every value within that range.

1. A particulate material comprising alumina hydrate, the particulatematerial having a 500 psi Compaction Volume Ratio of at least about 4.0cc/cc.
 2. The particulate material of claim 1, wherein the 500 psiCompaction Volume Ratio is at least about 5.0 cc/cc. 3-6. (canceled) 7.The particulate material of claim 1, wherein the alumina hydrate has ageometric aspect ratio of at least about 3.0. 8-11. (canceled)
 12. Theparticulate material of claim 1, wherein the alumina hydrate material isa seeded aluminous particulate material.
 13. The particulate material ofclaim 1, wherein the alumina hydrate is a metal oxide coated aluminahydrate.
 14. The particulate material of claim 13, wherein the metaloxide coated alumina hydrate includes a metal oxide selected from thegroup consisting of silica, tin oxide, vanadium oxide, tungsten oxide,manganese oxide, antimony oxide, niobium oxide, molybdenum oxide, andany combination thereof.
 15. The particulate material of claim 14,wherein the metal oxide is silica.
 16. The particulate material of claim13, wherein the metal oxide coated alumina hydrate includes a metaloxide having an iso-electric point of not greater than about 6.0. 17-21.(canceled)
 22. The particulate material of claim 1, wherein the aluminahydrate has an average particle size of about 30 nm to about 1000 nm.23-25. (canceled)
 26. The particulate material of claim 1, wherein theparticulate material has a pre-compaction loose packed density (LPD) ofnot greater than about 0.06 cc/cc. 27-28. (canceled)
 29. The particulatematerial of claim 1, wherein the particulate material has a HgCumulative Pore Volume of at least about 1.50 cc/g. 30-37. (canceled)38. The particulate material of claim 1, wherein the alumina hydratecomplies to the formula the formula Al(OH)_(a)O_(b), where 0≦a≦3 andb=(3−a)/2.
 39. The particulate material of claim 38, wherein 1≦a≦2. 40.A particulate material comprising metal oxide coated alumina hydrate,the particulate material having a 500 psi Compaction Volume Ratio of atleast about 4.0 cc/cc.
 41. The particulate material of claim 40, whereinthe metal oxide coated alumina hydrate includes a metal oxide having aiso-electric point of not greater than about 5.0.
 42. The particulatematerial of claim 40, wherein the metal oxide coated alumina hydrateincludes a metal oxide selected from the group consisting of silica, tinoxide, vanadium oxide, tungsten oxide, manganese oxide, antimony oxide,niobium oxide, molybdenum oxide, and any combination thereof.
 43. Theparticulate material of claim 42, wherein the metal oxide is silica.44-46. (canceled)
 47. The particulate material of claim 40, wherein themetal oxide coated alumina hydrate has a geometric aspect ratio of atleast about 3.0.
 48. (canceled)
 49. The particulate material of claim40, wherein the particulate material has a Hg Cumulative Pore VolumeIndex of at least about 3.0 cc/cc. 50-81. (canceled)
 82. A method ofmaking a particulate material comprising: adding a inorganic saltcomprising an oxidized metal anion to an alumina hydrate suspension; andadding an acidifying agent to the alumina hydrate suspension; whereby alayer of metal oxide is precipitated onto alumina hydrate particles ofthe alumina hydrate suspension to form the particulate material.
 83. Themethod of claim 82, wherein the alumina hydrate particles comply to theformula Al(OH)_(a)O_(b), where 0≦a≦3 and b=(3−a)/2.
 84. The method ofclaim 82, wherein the alumina hydrate suspension is an in situ SOL. 85.The method of claim 84, wherein the in situ SOL comprise seeded aluminahydrate particles.
 86. The method of claim 82, further comprisingmodifying the isoelectric point of the alumina hydrate suspension priorto adding the inorganic salt.
 87. The method of claim 86, wherein themodifying includes adding citric acid to the alumina hydrate suspension.88-98. (canceled)
 99. The method of claim 82, wherein adding theinorganic salt includes adding a sufficient amount of the inorganic saltto form a coating comprising about 10 wt % to about 50 wt % of theparticulate material.
 100. The method of claim 82, wherein adding theinorganic salt includes adding an inorganic silicate salt. 101-164.(canceled)